A secure area or service is that to which a designated or authorised person is permitted to have entrance or access. One of the most reliable means for ensuring that access to a particular area or facility is limited to only those persons of proper authorization is that of operating a manned security station, for human recognition and verification of persons designated for entry and or egress. Operating a manned security stations is very expensive. Of lesser degrees of expense are other mechanical and or electrical locking devices intended to prevent a door or other object from being opened, moved, or operated.
The oldest key-operated lock still in existence was found in the citadel of King Sargon II. The citadel was built in the Assyrian capital of Khorsabad in the late 700's B.C. Similar locks are shown in Egyptian art dating from about 2000 B.C.
A key-operated lock opens after a person inserts and turns the correct key. Such keys may be lost and such locks are sometimes of little deterrent to a practised and determined intruder.
A combination lock is opened by pressing a series of buttons on a keypad or by turning a dial to the correct sequence of numbers or letters. However entry codes or combinations are often forgotten, as users have no reliable method of remembering them. A written record of a preset code, particularly if kept in close proximity to a keypad, tends to be self-defeating. Regular code changes may improve security but the nuisance for both users and administrators discourages such precaution.
A password lock is similar to a combination lock but usually permits a user to determine their personal password. Most users choose passwords, which are easily remembered such as a birthday, a name of a pet or a nickname. A potential intruder with a little research into the backgrounds of a few designated users may derive a short list of potential passwords and hence many password systems may be accessed through a simple trial and error process.
Some electronic locks are opened by inserting a specially coded “key card”, that is cards or keys that have their codes on a microchip or a magnetic strip. A device reads the code and sends the information to a computer. If the code matches the one in the computer's memory, the locking mechanism is released. A potential intruder is usually discouraged by a key card reading security system, unless the intruder is in possession of a card which may have been sold, lost or stolen. Further, when there is no human monitored security at a particular portal, the unauthorized use of a key card is not detectable posing a significant security threat.
Some other electronic locks are opened after a computer has identified a biometric feature of the person desiring access. A biometric characteristic security system identifies a person by using a computer to compare the unique features of a fingerprint, palm, foot, voice, eye, signature or the like, with the a one in its memory. In a fingerprint system, for example, a person who wants to open a door, places his or her finger on a plate or platen mounted on or nearby the door. A scanner scans the finger's print and if it matches predeposited information in the computer's memory, the door is unlocked.
One disadvantage of biometric security systems is that the improved security offered by such systems is often overshadowed by the capital cost associated with purchase installation and administration. As such biometric security systems are typically limited to use in high-security areas, such as nuclear power plants and the like. Such systems are economically impractical for security in relation to small facilities such as multiple unit dwellings, or an individual residence, for example.
Another disadvantage of all the security access systems so far reviewed is that of being vulnerable to being rendered inoperative by vandalism. For example, a keyway or card slot may be filled with some foreign substance rendering the lock inoperative and denying access to all. Furthermore any mounted publicly accessible card reader, keypad, keyboard, or platen of a biometric characteristic reader, may be smashed with a heavy instrument or otherwise rendered inoperative.
One solution to the problem of vandalism has been to provide each user with a hand-held portable fingerprint recognition and transmission device, for example as disclosed in U.S. Pat. No. 6,111,977 to Scott et al. Their device includes a fingerprint scanner that encodes a fingerprint and sends the encoded fingerprint, via an infrared or a radio frequency transmitter, to a receiver in the secure item, facility or area. It is nonetheless necessary to have a central computer that analyzes the encoded fingerprint to allow recognition and authorization of an individual. The fingerprint scanner functions in conjunction with a keypad with several push buttons for selecting specific operations. By way of illustration one may consider for example, in combination with the correctly acceptable fingerprint, one push button will open all the doors of a car, while another push button opens only the car's trunk. The keypad may also be used for activating the fingerprint scanner.
The fingerprint scanner may be provided by a mechanism having a prism and a light source for reading the print of a finger or a thumb. The prism has a first or platen surface upon which a finger is placed. A second surface is disposed at an acute angle to the first surface to pass light reflected from the finger. A light is directed into the prism through a third or illuminated surface to illuminate the finger. Various examples of finger print reading devices using prisms are disclosed in U.S. Pat. Nos. 5,109,427 and 5,187,482 and 5,187,748 and 5,233,404.
A capacitive array fingerprint sensor is disclosed in U.S. Pat. No. 4,353,056 issued to Tsikos on Oct. 5, 1982. The described sensor has a two dimensional, row and column, array of capacitors, each comprising a pair of spaced electrodes, carried in a sensing member and covered by an insulating film. The sensors rely upon deformation to the sensing member caused by a finger being placed thereupon so as to vary locally the spacing between capacitor electrodes, according to the ridge and trough pattern of the finger, and hence, the capacitance of the capacitors. In one arrangement, the capacitors of each column are connected in series with the columns of capacitors connected in parallel and a voltage is applied across the columns. In another arrangement, a voltage is applied to each individual capacitor in the array. Sensing in the respective two arrangements is accomplished by detecting the change of voltage distribution in the series connected capacitors or by measuring the voltage values of the individual capacitances resulting from local deformation caused by the surface of the finger.
From a users viewpoint the hand-held security device disclosed by Scott et al is relatively bulky as compared to a key or a coded card and it may be misplaced lost or stolen.
From a manufactures viewpoint, reliability of the keypad in the hand-held security device is somewhat proportional to the expense of providing it. Although it is desirable to be able to provide an inexpensive mass producible the hand-held portable device, inexpensive key pad push buttons and the like are well known to become unreliable with frequent use. One possible modification of the Scott et al device is to eliminate the push buttons, however it is at least inconvenient and possibly a security risk to have all the car doors and the trunk unlock together, at the same time.
It is an object of the instant invention to enable a person to unlock any one portal exclusive of other portals by choosing which of their personal biometric characteristics is presented to a portable biometric device.